Motorcycle Body Protection: Helmets
The most important safety accessory in motorcycling today is the helmet. There are three basic styles, each with its advantages and disadvantages.
The half-coverage or "shorty" helmet was the early traditional helmet. It affords a good deal of protection for its light weight and offers better comfort, cooling, and ventilation than other models. The disadvantage is that you can't attach a decent face shield to the front of a shorty helmet and the coverage it gives to every part of your head except the top of your skull is effectively zero.
The open face helmet is the most popular motorcycle helmet for the street and trail rider around the world. Protection from this full-coverage helmet is much greater because it covers a larger area. You can easily add face shields to it. The only disadvantage of a full-coverage helmet is its extra weight and its tendency to limit neck movement.
The third helmet, the full coverage type, is the one that is recommended by far over all other types. While these helmets offer the greatest amount of protection in the event of a mishap, they do limit lateral vision, decrease ventilation, and fog glasses. Even after half a century of continued development, these problems still remain.
There are many factors to consider before you select a helmet to meet your needs. Be sure that you get a helmet that allows you full neck motion while riding. If you feel the rear of the helmet dig or prod into the back of your neck when looking up from a riding crouch, shop around for another helmet with more rear cutaway.
Weight alone does not determine the quality of a helmet. If the helmet seems very heavy to you, check it against others of the same general design. Be sure that the helmet meets the required government standards; select one that won't make you "neck weary" after riding several hours.
Of course the fit of a motorcycle helmet is the main factor in rider comfort. Never buy a helmet without trying it on! If the helmet hints the least bit of being too tight, go to a larger size. A tight new helmet can ruin your riding concentration and awareness by causing severe headaches. Remember: helmets don't wear-in like boots or leather jackets. Once you buy a tight helmet, you're stuck with it and all the headaches it causes, so avoid an "interference fit."
On the other hand, a helmet that is too loose doesn't offer the protection of one that fits properly. In addition, it can wobble on the rider's head, causing distorted vision through the face shield and other distractions.
I once had a mechanic friend who had to custom order helmets for his sizeable noggin... an 8 1/2 hat size! However it's good to know that special sized helmets can be special ordered!
Select a helmet that you can put on and take off easily and yet fits you comfortably. The helmet should be able to move slightly on your head until you cinch down the chin strap. After tightening the strap, there should be almost no helmet wobble. A tight chin strap is as important to your cranial protection as the fit of the helmet itself. If you over-tighten your chin strap and become uncomfortable, it's a simple matter to loosen the strap a bit. However, if you buy a helmet that's too tight, the only solution is a larger helmet. Or you could wash your head in hot water repeatedly until it shrinks... like some of the commenters on my CPU Lapping Hub.
Helmet manufacturers are not very consistent in sizing their helmets. One that is marked "Large" might fit you more tightly than another brand labeled "Medium."
If you have a serious accident and your helmet is involved, a new helmet should be purchased. The old one probably has some of the inner lining crushed and may have cracks in the shell. The inner lining does not return to its original shape after it has been dented.
Be selective. Your helmet will be with you through several motorcycles. It's the most important safety device you have, other than your own good judgment, so choose your helmet carefully.